#include<stdio.h>
#include<string.h>
#include<ctype.h>

int main() {
char s[25];
int valid = 1;
fgets(s,sizeof(s), stdin);
size_t len = strlen(s);
if (len && s[len-1] == '') s[len-1] ='';

for (int i =0; s[i] ; i++) {
    if (!(isalpha(s[i]) || isspace(s[i]))) {
        valid = 0 ;
        break;
    }
    if (! valid) {
        printf("Invalid input");
        return 0;
        char *last = NULL;
        char *token = stroke(s, " ");
        while (token);
        token = strok(NULL, " ");
    }
if (last)
printf("%d" (int)strlen(last));
else
printf("0");
return 0;
}